Multicolor film and method



ct. 3, 1933. T TRQLAND 1,928,709

uUL'rIcoLoR FILI 'AND mamon Filed Feb. ,1., 1950 Patented Oct. 3, 1933MULTICOLOR FILM AND METHOD Leonard T. Troland, Cambridge, Mass.,assignor, by mesne assignments, to Technicolor, Inc., New York, N. Y., acorporationof Delaware Application February 1, '1930. Serial No. 425,206

11 Claims.

This invention relates to photographic films, and more particularly tofilms employed in the art of color photography.

It has been proposed before to produce color photographs by coating abase with an emulsion sensitive to a certain part of the spectrum, thento recoat this emulsion with a second layer sensitive to a differentpart of the spectrum, and so on if desired, then to expose the wholeunit to the object to be photographed and subsequently to separate theemulsions for reproducing the image records. Various methods have beenproposed for separating the emulsions, but none of them isquitesatisfactory in actual practice, or at least they involve more orless complicated operations and great care.

It is therefore the principal object of my present invention to providea photographic lm with superimposed differentially sensitive emulsionsof peculiar construction, which permits a relativelyconvenientseparatlon of the color records, and to provide a method ofseparating the color aspects recorded on this film, in a commerciallyfeasible manner.

In order to facilitate the understanding of the following description, afew of the recurrent terms will bedefined. The term photographic film isemployed to include generically all photographic records or recordingarticles or devices, whether the emulsion is supported upon celluloid orother supports or is self-supporting, and whether the film is adaptedfor either still or moving pictures. The term emulsio is usedgenerically to connote either a true emulsion or any other compositionwhich is sensitive to light.

The invention involves a film having several coatings of dierentsensitiveness to light, as for instance, described in my Reissue PatentNo. 18,680, forcolor photography, of December 6, 40 1932, these coatingshaving in addition different characteristics lwith respect to theirsolubility. The layers may have different solubility either in one andthe same solvent at different temperatures or in different solvents.vAfter the light sensitive strata have been simultaneously exposed, thelayers are removed consecutively, with the exception of the layerimmediately upon the base, by dissolving each layer in a solvent notaffecting the remaining layers, and prints are made prior to eachprocess of -removing one layer, and from the last.'layer, for vthepurpose of deriving from these prints correct reproductions of thevarious color aspects as originally recorded on the different strata ofemulsion by known methods, of which examples will be given.

The invention will be explained by describing a simple, specificembodiment thereof by referring to the appended drawing, which shows asection through a iilm according to my invention.

B is the base of the film on which the iirst emulsion coating P is laid,which is sensitized to a particular color aspect as, for instance, withthe aid of carbocyanol, (Eastman) to the red and blue rays, but not togreen rays of the spectrum. first emulsion P comprises a hard gelatinewhich is insoluble or relatively insolublein water. This insolubility inwater can be Aobtained by any Well known means, as, for instance, bytreating the layer with chrome alum or with formalin, whereby great caremust be taken to prevent any penetration of the hardening agent toadjacent layers, which can'be attained by using-the minimum amount ofhardeningmaterial necessary to impart the desired degree of hardness tothe para ticular kind of gelatine employed. A second 76 emulsion coatingS is then applied over the first coating P, this second coatingcomprising an emulsion sensitized to a complementary color aspect, inthis case, blue-green, by dyeing it with a suitable dye as, forinstance, pinaflavol (I. G. F.) 80 This emulsion comprises gelatinereadily soluble in warm water of about 80 or above degrees Fahrenheit.If desired, a coating of color F may be superposed on the ultimatelayer. The lm prepared in this manner is nowl exposed in the` usual way,developed and a print made thereof which will preserve the compositepicture contained in the emulsion. This print will be re- Y ferred to ascomposite positive. The negative is then subjected to the action ofwater of proper temperature, and the surface layer containing theblue-green color aspect to be referred to as green negative, is therebyremoved. The layer comprising the hardened gelatine, to be referred toas red negative is now isolated and a print thereof can be made whichwill in this case contain the red color aspect and will be referred toas the red positive. Color prints can now be made by making an auxiliaryor so-called dupe negative from the composite positive and combining itwith the remaining layer of the original negative.

If the color separation thus obtained is inad-r equate, a method which Ihave described previously, for instance in my Reissue Patent No. 18,680,for color photography, of December 6, 1932, can be utilized forobtaining better results. This method comprises the following steps: Anegative is made from the red positive, superimposed in registry uponthe composite positive, and a print made therefrom. This will be apositive of the green negative which had been removed by dissolving itsemulsion in warm water, the red aspect having been subtracted from thecomposite positive. A green negative? can now be made from this positiveso that, together with the original red negative two regular negativesare now available which can be further utilized by any desired process.

From the foregoing it will be apparent to any one skilled in the artthat my invention isnot limited to the embodiment above described, butthat it can also be employed for `iilms containing more than two layersof differential color sensitiveness and with differentially solubleemulsions, that it is furthermore not conned to the use of water asetching means but that any solvent or combination of solvents whichpermit a differential etching of superimposed strata can be employed,and that is not essential whether the combination emulsion is exposed inthe mannerv described or through .the lm, provided that the strata andfilter coating have been arranged accordingly.

I claimz 1. In the art of making color photographs by recordingdifferent color aspects on diierent superimposedparts of a lightsensitive emulsion, the method of separating said color aspects, whichmethod comprises the simultaneous recording of different color aspectson said different parts of the emulsion, in copying the combinedrecords, in subsequently separating said parts by consecutivedifferential dissolving, and in making prints of the records remainingafter each dissolving operation. y

2. In the art of making color photographs by recording different coloraspects on two superimposed parts of a light sensitive emulsion, themethod of separating said aspects, said method comprising thesimultaneous recording of two color aspects upon said two lightsensitive parts of said emulsion, and in separating the two parts bycopying the combined aspects, dissolving the outer part, copying theremainder and combining the copy of the combined aspects with that ofthe remainder for obtaining a copy of the aspect upon said dissolvedpart.

3. The method of making color photographs, which method comprisessimultaneous printing of two color aspects upon two layers of emulsion,one layer being insoluble and the/other soluble in hot water, indeveloping the composite image record, in making a positive of thecombined record, in dissolving the outer layer in hot water, insuperimposing the remaining layer upon the positive of the compositerecord, and in making a print from the superimposed records.

4. A lm for making color photographs by recording different coloraspects on different layers of the emulsion of the illm, characterizedin that the diterent layers have a different color sensitiveness anddifferent solubility in hot water, the solubility increasing from theinnermost towards the outer layer.

5. A photographic lm having a base and an emulsion comprising aplurality of layers sensitive to different parts of the spectrum and ofdifferent solubility in a certain solvent of varying temperature, thesolubility of said layers in said solvent increasing from the layer nextto the base toward the outermost layer with steadily varyingtemperatures of said solvent.

6. A photographic film comprising a base and emulsion upon said base,said emulsion being sensitive to a certain range of the spectrum andsubstantially insoluble in hot water, and a second emulsion upon saidfirst emulsion, said second emulsion being sensitive to a diierent rangeof the spectrum and substantially soluble in hot water. v

7. Av photographic lm having an emulsion comprising layers of differentsensitivity to spectral colors and of correspondingly differentsolubility in a certain solvent, the solubility increasing from theinnermost towards the outermost layer.

8. A photographic lm comprising silver halide emulsion layers ofdifferent sensitiveness to spectral colors, each layer being soluble ina diierent solvent.

9. A photographic nlm comprising a baseand an emulsion consisting of aplurality of layers sensitive to different parts of the spectrum and ofdiierent solubility in water of different temperature, the solubility inwater increasing from the layer next to the base toward the outermostlayer.

10. A lm for making color photographs by recording different coloraspects on diierent layers of the silver halide emulsion of the lm,characterized in that each layer has color sensivity and solubilitycharacteristics substantially diierent from the corresponding propertiesof the other layers.

11. A photographic lm having a base and a silver halide emulsioncomprising two layers with different solubility ina certain solvent aswell as different color sensitivity.

LEONARD T. TROLAND.

